systemd's postgresql.service

gistfile1.txt

[Unit]
Description=PostgreSQL database server

[Service]
Type=forking
SyslogIdentifier=postgres
PIDFile=/var/lib/postgres/data/postmaster.pid

# initdb script takes care for symlinking $PGROOT to /var/lib/postgres
ExecStartPre=/usr/lib/systemd/scripts/postgresql-initdb
ExecStart= /bin/su - postgres -m -c "/usr/bin/pg_ctl -s -D /var/lib/postgres/data start"
ExecReload=/bin/su - postgres -m -c "/usr/bin/pg_ctl -s -D /var/lib/postgres/data reload"
ExecStop=  /bin/su - postgres -m -c "/usr/bin/pg_ctl -s -D /var/lib/postgres/data stop -m fast"

# Due to PostgreSQL's use of shared memory, OOM killer is often overzealous in
# killing Postgres
OOMScoreAdjust=-200

[Install]
WantedBy=multi-user.target

Getting error at the time of start. postgresql.service: Failed at step EXEC spawning /bin/su: Permission denied